The Ukrainian loses the IBF title just weeks after becoming the undisputed heavyweight boxing champion of the world.

The Ukrainian, 37, became the first heavyweight to hold the IBF, WBO, WBA and WBC belts when he beat Tyson Fury in a split decision in Saudi Arabia last month.

With Usyk now contracted to a rematch with Britain’s Fury, he is not in a position to defend the IBF crown against interim champion and mandatory challenger Daniel Dubois.

That means Dubois’ expected all-British fight against Anthony Joshua at Wembley in September could now be for the vacant title.

Usyk said in a video posted on social media: “Anthony and Daniel, listen. I know the IBF title is important to you. It is my present to you on September 21.”

Britain’s Lennox Lewis was the last man to unify the major heavyweight belts – three at the time – prior to Usyk, in 1999.